The invention relates to a disk brake.
The invention particularly relates to novel constructions of disk brakes, particularly for commercial vehicles, which are actuated pneumatically and/or electromechanically.
According to the principle selected for introducing power, disk brakes can be divided into two basic designs:
1. The generation of power and the wear adjustment on both sides of the brake disk; for example, a hydraulic fixed caliper disk brake with a fixed brake disk relative to the axle, and the generation of power on both sides of the brake disk, and
2. the generation of power and the wear adjustment on one side of the brake disk and the transmission of the actuating power to the side which faces away, according to the reaction power principle; for example, a sliding caliper disk brake, a hinged caliper disk brake, or a fixed caliper disk brake with a slidable brake disk.
Pneumatically actuated disk brakes for heavy commercial vehicles with rim diameters of 15 inches or more normally use the reaction power principle because, as a result of the narrow installation conditions at the vehicle wheel, the arrangement of a pneumatic operating cylinder is only possible on the vehicle interior side of the wheel open toward the vehicle interior. Constructions of these types are shown, for example, in German Patent Document DE 36 10 569 A1, German Patent Document DE 37 16 202 A1, European Patent Document EP 0 531 321 A1 (see particularly the construction of the adjusters along the lines of rotary drives) and European Patent Document EP 0 688 404 A1.
Sliding caliper or hinged caliper disk brakes require a component which is fixed with respect to the axle—generally called a brake anchor plate (carrier)—which holds or guides the brake shoes/brake pads and, when the brake is actuated, absorbs their peripheral forces and carries the caliper which is slidably disposed coaxially to the vehicle axle.
The relative motion carried out by the caliper with respect to the component fixed relative to the axle can be divided into the working stroke and the wearing stroke. The invention makes surprising use of this effect.
The working stroke is carried out with each actuation of the brake in order to overcome the release play of the brake and to compensate for the elasticities of the brake pads and the caliper that result from the application of power. Depending on the extent of the actuating power and the amount of the release play, it is normally <4 mm.
In contrast, the wearing stroke is the wear adjusting travel which the caliper carries out over a large number of brake actuations in order to compensate for the wear on the reaction side of the brake. The wearing stroke is composed of the wear of the outside brake pad and the wear of the brake disk friction surfaces situated on the outside, and normally amounts to up to 25 mm.
In comparison, in the case of the brake design with a fixed caliper and a slidable brake disk, the working stroke and the wearing stroke are generated by sliding the brake disk.
The designs with the sliding caliper or hinged caliper have the disadvantage that the brake anchor plate, fixed relative to the axle, is required for absorbing the peripheral force of the brake pads and the holding and guiding of the caliper. This component results in additional cost and additional weight. Furthermore, the required sliding guidance or hinge system is susceptible to problems.
In the design with the slidable brake disk, in contrast, the problem is in maintaining easy slideability of the brake disk on the guiding area of the hub throughout the entire service life. An effective sealing-off can hardly be implemented because of the narrow installation conditions and the harsh environmental exposure.
Based on this background, the invention starts with the idea of combining the advantages of the above-described caliper concepts and thereby achieves, among other things, the objective of simplifying the construction of the disk brake and reducing its overall weight relative to sliding caliper brakes.
The invention achieves this task by means of the objects of the invention. Accordingly, in each case, at least one adjusting device is provided on each side of the brake disk for adjusting the axial distances between the two brake pads and the brake disk.
Furthermore, according to the invention, the generation of the reaction power takes place on the side of the brake disk facing away from the application side by                the sliding of the caliper and/or        the swivelling of the caliper and/or        the sliding of the brake disk.        
In each case, as the result of the sliding and/or swivelling motion, essentially only the length of the entire power stroke can be bridged.
The invention combines the advantages of the fixed-caliper principle —such as compact construction and implementation of the wearing stroke by the actuating system—with the advantages of the reaction power principle.
As an alternative or in addition, it is also contemplated that the generation of the reaction power takes place on the side of the brake facing away from the application side by an elastic deformation of the caliper and/or of the brake disk and/or of another element, by means of the deformation essentially only the path of half the entire power stroke being bridgeable. In this case, bearings of the brake disk or of the caliper can advantageously be further reduced or even completely eliminated. Elastic brake disks are known per se, for example, from German Patent Document DE 198 10 685 A1.
As a result of the additional adjusting device(s) on both sides of the disk brake, it is permitted to further develop the brake such that only a mobility, preferably a slidability and/or a swivellability of the caliper and/or the brake disk have to be ensured, which is dimensioned such that the working stroke during brakings can be bridged in order to apply the brake. In this manner, the sliding and/or rotary bearings and guides can be dimensioned to be correspondingly smaller and less expensive. Additionally, it is ensured that a smooth running takes place along the complete sliding or swivelling path since the latter is bridged during virtually every braking.
The brake disk is preferably constructed as a sliding disk which is slidably guided on a brake disk hub such that, as a result of the sliding, a sliding path can be implemented which is maximally limited to the power stroke.
As an alternative or in addition, the caliper can be constructed as a sliding caliper, which has a sliding caliper bearing which can be fastened directly to the axle flange and which is dimensioned such that a sliding path can be bridged which is limited to the power stroke.
As an alternative or in addition, the caliper may be constructed as a hinged caliper which has a hinged caliper bearing, which preferably can be fastened directly to the axle flange and can be bridged by means of the swivelling angle which displaces the caliper relative to the brake disk essentially by the amount of the power stroke.
In particular, the disk brake according to the invention makes it possible to continue to arrange the power generating device—such as a pneumatically actuated and/or electric-motor-actuated brake cylinder or an electric drive—only on one side on the brake.
Additional objects, which can also be considered independently, can also be achieved within the scope of the invention.
A variant, which can also be considered independently, of the invention solves the problem of the joint adjustment of the adjustable rotary drives on both sides of the disk brake. Here, the adjustable rotary drives on both sides of the brake disk are mutually coupled by means of a synchronizing device. The synchronizing device is preferably constructed as a coupling mechanism or as an electronic coupling system.
According to another variant, which can also be considered independently, of the invention, the adjusting system itself is constructively further improved. This variant, in the case of which a space-saving adjusting module is created, which can be produced particularly economically, is suitable for brakes of a conventional construction as well as for brakes of the type claimed.
According to the invention, the adjusting system on one or both sides of the brake disk is constructed as an adjuster module, which can be preassembled and which has at least                an electric motor as the drive,        a reduction gear connected behind the electric motor,        which can be mounted preferably jointly on a mounting preform, particularly a mounting plate or preferably between two mutually spaced mounting preforms, and        wherein the rotary drive(s) are inserted on/in the at least one mounting preform(s).        
Finally, according to another variant of the invention, which can also be considered independently, the construction of the application device itself is simplified. In this case, the application device arranged in the caliper has a rotary lever, which can be operated by a rod, preferably a piston rod. The rotary lever has a recess for receiving the piston rod end on one of its ends, and on its end area facing away from the recess, has recesses on two of its exterior sides. In these recesses, essentially spherical-cap-shaped bearing shells and/or essentially ball-shaped bearing elements or bearing balls can be inserted for bearing the rotary lever. By these means, the rotary lever is disposed directly or by way of additional intermediate elements, on the caliper-lever bearings—and directly or via additional intermediate elements on at least one thrust piece used for displacing the brake pad in the direction of the brake disk-eccentric bearing.